Structural dynamics of phenylisothiocyanate in the light-absorbing excited states: Resonance Raman and complete active space self-consistent field calculation study

Journal Article · Wed May 21 00:00:00 EDT 2014 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4875807· OSTI ID:22254866

Ouyang, Bing; Xue, Jia-Dan; Zheng, Xuming ^[1]; Fang, Wei-Hai ^[2]

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1. Department of Chemistry, Zhejiang Sci-Tech University, Hangzhou 310018 (China)
2. Department of Chemistry, Beijing Normal University, Beijing 100875 (China)

The excited state structural dynamics of phenyl isothiocyanate (PITC) after excitation to the light absorbing S{sub 2}(A′), S{sub 6}(A′), and S{sub 7}(A′) excited states were studied by using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The UV absorption bands of PITC were assigned. The vibrational assignments were done on the basis of the Fourier transform (FT)-Raman and FT-infrared measurements, the density-functional theory computations, and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohexane, acetonitrile, and methanol solvents were, respectively, obtained at 299.1, 282.4, 266.0, 252.7, 228.7, 217.8, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PITC. The results indicated that the structural dynamics in the S{sub 2}(A′), S{sub 6}(A′), and S{sub 7}(A′) excited states were very different. The conical intersection point CI(S{sub 2}/S{sub 1}) were predicted to play important role in the low-lying excited state decay dynamics. Two major decay channels were predicted for PITC upon excitation to the S{sub 2}(A′) state: the radiative S{sub 2,min} → S{sub 0} transition and the nonradiative S{sub 2} → S{sub 1} internal conversion via CI(S{sub 2}/S{sub 1}). The differences in the decay dynamics between methyl isothiocyanate and PITC in the first light absorbing excited state were discussed. The role of the intersystem crossing point ISC(S{sub 1}/T{sub 1}) in the excited state decay dynamics of PITC is evaluated.

• OSTI ID: 22254866
• Journal Information: Journal of Chemical Physics, Vol. 140, Issue 19; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
ABSORPTION
ACETONITRILE
CYCLOHEXANE
DENSITY FUNCTIONAL METHOD
EXCITATION
EXCITED STATES
FOURIER TRANSFORMATION
INTERNAL CONVERSION
ISOTHIOCYANATES
METHANOL
NORMAL-MODE ANALYSIS
RAMAN SPECTRA
RAMAN SPECTROSCOPY
RESONANCE
SELF-CONSISTENT FIELD
SOLVENTS
WAVELENGTHS